7D II or 100-400mm II?

I now use the 7D and 100-400mm for nature/wildlife, including lots of birds in flight. Portability is important to me, as I do a lot of hiking and shoot mostly hand-held. I have the Canon 1.4 II extender, though I can't use it with auto-focus with my 100-400.

I probably can't justify both the II versions of my camera and lens, though each has new capabilities that would be useful to me. I'd appreciate any thoughts on which one I should buy.

Thanks for all thoughts.

(Should I post this on the lenses forum, too, or can I assume most of the same people frequent both?)

Combining the 7D Mark II with the EF 100-400 mm f/4.5-5.6L IS USM together with your EF 1.4X extender will indeed give you AF even at f/8. But using the 7D with the EF 100-400 mm f/4.5-5.6L IS II USM and the extender will not.
According to everyone who have tried, the image quality of the new lens is better than the old one.

Do you like the push-pull zoom of your current 100-400 mm? Maybe that's just as important a question to answer here.

But disregarding that part, I think the new camera will benefit you more.

I do like the push-pull, but have little experience with a zoom ring for birding-type applications, so I'm willing to assume that I would become comfortable with a zoom ring with use.

I'm leaning toward the new camera, as you suggest. Among other benefits, my 7D will become a good second body that I can use with other lenses to minimize the need to change lenses in the field.

Thanks for the comments.